Field of the Invention
This invention relates to a method for measuring stroke volume, and more particularly to a method for measuring stroke volume of a right ventricle.
Description of Related Arts
As early as 1950s-1970s, cardiologist recognised the importance of right ventricle function in heart filter, congenital heart disease and pulmonary hypertension. The assessment of right ventricle congenital function and anatomy remains a big challenge using two-dimensional echo because of its complex geometry. With poor resolution of two-dimensional image and the pre-processing which leads to possible loss of information, the right ventricle modelling is very difficult and inaccurate. The right ventricle stroke volume is an important measure of right ventricle function. Therefore, there is a need for an accurate method of measuring the stroke volume.
U.S. Pat. No. 4,674,518 disclosed a cardiac monitoring apparatus, more particularly to a method and apparatus for quantitatively measuring the instantaneous ventricular volume contained within a given chamber of a heart using an intracavity electrical impedance catheter having plural pairs of spaced surface electrodes driven by a corresponding plurality of electrical signals, each of the signals exhibiting a different discrete frequency, and having plural pairs of spaced surface electrodes for sensing the potentials at predetermined locations within the ventricle. The apparatus enable stroke volume and cardiac output to be continuously monitored. The cited patent involves the use of catheter which needs to be inserted into patient's body and this could cause discomfort and pain to the patient while the monitoring is taking place.
Kovalova et. Al. (2005) disclosed optimal geometric model for two-dimensional volumetry of right ventricle and its clinical validation. It disclosed that an ellipsoidal shell model best reflects the complex right ventricular geometry. Measurements of right ventricular stroke volume were made in modified apical four chamber and parasternal short axis views both in end-diastole and end-systole. The cited article mentioned that some of the result has poor quality of echocardiographic images. Besides that, the cited article used two-dimensional echocardiography which produces low precision of result and did not account for the variability of right ventricular outflow tract in patients.
Accordingly, it can be seen in the prior arts that there exists a need to provide a method for measuring stroke volume of right ventricle that is not painful to patient and has a better visualisation and accuracy of the end result.